How The Channel Tunnel Works

Let's dive into the engineering and construction of the Channel Tunnel on its 30th anniversary.

It is a challenging endeavor to put any tunnel below the sea, and this monumental project faced some monumental hurdles. From complex cretaceous geology, to managing air pressure, water pressure, and even financial pressure, there are so many technical details I think are so interesting about this project.

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This is not engineering advice. Everything here is for informational and entertainment purposes only. Contact an engineer licensed to practice in your area if you need professional advice or services. All non-licensed clips used for fair use commentary, criticism, and educational purposes.

SPECIAL THANKS
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This video is sponsored by Brilliant.
Stock video and imagery provided by Getty Images, Shutterstock, and Videoblocks.
Tonic and Energy by Elexive is licensed under a Creative Commons Attribution License
Video by Grady Hillhouse
Edited by Wesley Crump
Produced by Ralph Crewe
Graphics by Nebula Studios

[PracticalEngineeringChannel]

🚆 Have you ridden through the Channel Tunnel? What was your experience?

[Ven]

As someone who's taken the Eurostar several times, I can assure you it's far better than flying. There's a reason why those fights have to be cheap because they have to undercut the price of the train. The train will offer far more comfort, space, and amenities than those typical short haul airliners. Being able to leave downtown London and be in downtown Paris within 2 hours is amazing. Depending on the price of the ferry, the automobile driver can choose to take the train all the ferry. I once traveled from London to Munich all by train. First leg was the Eurostar to Paris and then I took a TGV from Paris to Munich. Sure, I could have saved time by flying straight from London to Munich, but the train trip was far better. During my stopover in Paris, I was able to explore the city before catching the next train.

[ryanm.]

I’m from the U.K. and am right now currently skiing in Austria having taken the channel tunnel here and will use it to return. I have used it twice a year for twelve years and the logistics behind it all is immeasurable.
The trains are very punctual, they’ll load more than 100 cars in 15-20 minutes and provide this service four times an hour in off seasons and six to eight times an hour in peak holiday seasons.
And even though it was designed now almost 40 years ago, the trains and every looks modern still

[startide]

One thing we can see in the video (well if you looked in the background) is that the service vehicles actually have dual cabins for driving. Since they can't possibly turn around in the service tunnel, crew members simply change cabin and drive the other way.

[gjwdavies]

My father was a Civil engineer on this project. Still one of his favourites. He has a lot of great stories about the construction. Can't wait to show him the video.

[neatodd]

Good video. I used to work for Eurotunnel. I could leave my flat in Folkestone in the morning, go through the tunnel to France for a meeting and be back in my office in the UK by lunchtime (sometimes taking the opportunity to buy a few bottles of French wine in a local supermarket before returning).
It's amazing to me that the tunnel has made it possible for freight trains to run all the way from China to London.

[sarkybugger]

I am proud to say that I contributed to its construction, in a small way. I worked there as a loco driver for a couple of years, with the hand tunnelling gangs that dug the cross-passages and piston relief ducts on the land drives. Made a few trips to the marine TBMs, delivering ring segments and grout. Quite intimidating machines, the first time you drive inside one. They're huge. The crossovers were even bigger before they put the doors in.
I still have my tallies, a TML t-shirt that still fits, and my breakthrough medal. Oh, and a 5lb ammonite that I pulled off the conveyor belt, before it disappeared for another few million years. 😁
Best wages this part of the country had ever seen, which was a bonus...
The disadvantage was that now that HS1 is open, people from London have moved to Folkestone in large numbers, pushing house prices through the roof.

[rennaaa]

I wish we'd see more mega infrastructure projects like that. The moment they met in the middle and drilled trough to the other tunnel must have been such an amazing moment for the people that built it.

[billymcmedic]

Another nice detail about the channel tunnel is that it allows new built trains to be transported from mainland Europe to the UK without needing to be loaded onto a boat and floated across, resulting in lots of faffing around to get them on and off, simply hook the train to be delivered to one of the tunnel freight locomotives and they can be pulled through. It’s how the new Mersey rail and Tyne and Wear metro trains are being delivered from stadler in Switzerland, they get pulled by train to Calais, transported through the tunnel, and hooked onto another train for final delivery (usually a pair of Down geared HST powercars)

[fonkbadonk]

I once took a weekend trip from Germany to London with a travel agency. They just drove their big coach into one MASSIVE train, and then into the tunnel we went. Absolutely incredible. And the ride was suuuuper smooth. There was just one spot where we felt an ever so slight bump, the rest not a single vibration. It was also cool to get off the coach and walk around in that huge rail car, meeting people from other coaches.

[jakobrebeki]

I worked on the channel tunnel and for me the best part was working in the cathedral (the crossovers in the middle). I was lucky enough to be at the break thru party as well. what a great job to be on....

[ianp]

When I was a kid, I was devastated when I found out it wasn’t a glass or Perspex tunnel laying on the sea floor so you could see out. Still am, to be honest!

[BnORailFan]

I have traveled through the Channel Tunnel twice, first by car on the train, second as strictly a passenger. When going by car I was standing next to it waiting to start moving and said out loud when will be be going, then I looked out the small window and saw that we were already moving. That was the smoothest train ride I have ever been on. Very impressive.

[MCP]

Nice one Grady! I'm a Brit and I've used the Chunnel twice so far. We were relocating the whole family from Vaasa in Finland to Devon in the SW of England. That involved one car, and a big van driven by myself. The route was 'simple' enough, drive from Vaasa to Turku, a ferry from Turku to Stockholm, drive across the big bridge from Sweden to Denmark, keep driving and the Chunnel awaited. Drive onto the train, twiddle thumbs and get off in Dover - then a big drive west.
The second was returning the van!

[RILDIGITAL]

An impressively informative video, truly brings to life the sheer scale and daring of this mega project. It's astounding to comprehend the amount of engineering knowledge and expertise it took to bring the Chunnel into reality.

[ce]

This project was the reaching of centuries of ambition, even today, one of the most iconic engineering marvels - you get on a high speed train city centre to centre up to 300km/h on other sections, or drive your car onto a train! A second Channel crossing would be great imo

[freebirdofreason]

I was 27 when i started working during construction of this tunnel, i worked underground for most of the construction.
A very Dangerous job but a very memorable experience as a young lad, a dirty hot and dusty environment.
I then went on to drive the trains through for Eurotunnel for many years.
Now retired, the tunnel paid my mortgage, although we must remember all that lost their lives during construction, about 14 I seem to remember.

[ZeroNneZero]

Hi, I’m from Cincinnati, Ohio, where our railway revitalization was sabotaged and then buried like it never happened. The fact that two separate countries built an underwater railway that still functions well to this day is both thrilling and discouraging. I feel like Cincinnati could easily have a decent rail system but year after year, it just continues to decay under the ground.

[Deltarious]

For me the fact that the tunnel *has* turned a profit, at all, and is such a monumentally large, complex and technologically innovative project proves beyond all doubt that it absolutely should have been built. Plus the better rail gets in both countries the more appealing it is as an option

[mirskym]

By the way, I bought your book and my grandchildren aged 8 - 10 love it! They think the hard hatted engineer is funny but they are really learning. A source of pleasure for me as I am a retired Electrical Engineer (Power Systems).